Manually operable thermostatic switch assembly



Aug. 29, 1950 F, R BEAN' 2,520,873

mmm! oPERABLE 'mnos'rA'rIc swrrca ASSEMBLY Filed oct. 19. 1 942 Frank Robe/' Bean INV ENT OR.

Psanad Aug. ze, 195o MANUALLY OPERABLE TBERMOSTATIC SWITCH ASSEMBLY Frank Robert Bean, Rochester, N. Y.. assigner to F. A. Smith Manufacturing Company, Roch'- eater, N. Y., a corporation ot New York Application october-'119, 1942, semi No. 462,504

2 Claimi.

The present invention relates to a manually operable thermostatic switch assembly and more particularly to the combination with a thermostatic switch assembly of a means movable to two positions and which may be manually operated to re-set or return the thermostatic element of a thermostatic switch to a closed or operative position. The use of thrmostatically operated'switches to interrupt an 'electric circuit under predetermined and/or abnormal conditions is well known. However, it is alsov necessary and desirable to manually control the position of the switch element of such an'assembly and move the same to an on and/or oiiI position irrespective of the load conditions in the circuit including the thermostatic element. n l y The primary object of the present invention is the provisionoi a'manually operable member movable to either of two4 positions and forrendering the themostaticelement of a thermostatic switch assembly operative when said member is moved to onejof its positions.

Another object o! the invention is the co'mbination with a switch means including a. snap acting thermostatic switch arm, of a manually operable re-set jmember for permitting return of said switch arm to a closed position. i

The foregoing and other objects of the invention are embodied in the combination of a thermostatic switch assembly having a normally closed switcharmga manually operable member movable to either of two positions. and an intermediate means operatively connected to said manually movable member. v

Reference is hereby made to the accompanying drawings wherein similar reference characters designate similar elements and wherein:

Figs. 1 and 2 are vertical longitudinal cross-sections of the preferred embodiment of the manually operable thermostatic switch assembly showing the sam'e respectively in closedand open positions.

Fig. .3 is a horizontal section of said preferred embodiment and taken on the line 3 3 of Fig. 1.

The illustrated embodiment of the invention asshown in Figs. 1-3 inclusive. includes a thermostatic switch arm which can be held in an open position, and includes an intermediate means normally opening said switch arm but releasably maintained in an ineffective position (Cl. 20G-116) 2. bers is arranged so as to hold the intermediate member in an ineiective position and may be operated by the thermal operation of the switch arm to permit movement of said intermediate member to normal position and to open said switch arm.

In said illustrated embodiment, the assembly is enclosed in a casing 22a which is fastened by rivets 23 to a mounting plate 20a. An insulating base 24a is held by tongues 25a. in one side of said casing 22a. The thermostatic switch arm 3i may be mounted in any suitable manner upon the basetta as by being riveted to the head 50 of a terminal stud lI which has a threaded portion 52 carrying a washer 5 3 anda nut 5I for attachment to said base 24a.VThe contact 35a on switch arm 3| normally engages the contact 28a which is mounted upon the head 55 of a terminal stud 56 which has a threaded portion 51 carrying a washer 58 and nut 59 for attachment to said base erable member are both mounted upon a bracket' and released by thermal operation of said thery mostatic switchy arm whereupon said arm is moved to open position. A toggle means between 24a. The conductors to the circuit t'o be controlled by switch arm Il are attached to said terminal studs 5I and 5B.

The intermediate member and manually op- 60 which is fastened to base 2da by rivets 6I and which bracket'll has Side walls 52 with overhanging portions for supporting the manually operable member. Said intermediate member and manually operable member each have two positions, the intermediate member having ineffective and operative positions corresponding to an on and an oit"'position of the manually operable member.

The intermediate member is preferably a pivoted lever and may comprise a pair of arms 53 oppositely bent at both ends. the ends S3' being bent at right angles for attachment by rivets L4 to a plate B5 and the ends 63" being bent and perforated to pivot upon a pin 68 which extends between side walls 62 of bracket 50.' Said plate 65 isprovided with an aperture B5' into which extends the projection 31 oi' the switch arm 3i. A spring member 51 has one end attached to a hole E8 in said arms 53 and has its other end fastened to a post 69 on one oi' said side walls 62. The normal action of spring member 51 is to hold the intermediate member in the extreme position shown in Fig. 2 with the lower vportion of plate 65 engaging the lower face oi' projection 31 and holding the switch arm Il with contacts 28a and 36a separated. y

The manually operable ,member according to the invention comprises a bell crank member 10 the intermediate and manually operable `mem- 55 which is rotatably mounted upon a shaft 1i exandere tending between the overhanging portions of side walls 62 and which is spaced from one of said side walls 62 by a sleeve 12. One arm 1l oi member extends through slots 22' and Il in casing 22a and plate 20a and has threaded thereon a handle 14 while the other arm 1S oi member 10 is within casing 22a. A toggle or tripping means comprises a pair of link members 1l. each having one end pivotally connected to the arms i3 of the intermediate member by a pin 11, another end pivotally connected to the arm 18 of the manually operable member by a pin 18, and each having a projection 1l adapted and arranged to be engaged by the thermostatic switch arm 3i when the same is heated and moved to open position thereby.

The oil position of the thermostatic switch assembly is shown in Fig. 2 and in such position the spring 61 holds the intermediate member in its upper extreme position with contacts 2.a and 16a separated and with handle 14 of the manually operable member in a right-hand position which can be immediately distinguished from its other position and recognized as indicating that the switch assembly is open.

Said switch assembly is placed in on position by movement of the manually operable member such as by moving handle 1I in a counter-clockwise direction from the position shown in Fig. 2 to that shown in Fig. l. .As the handle 14 is s0 moved, the bell crank member 1l and arm 15 thereof are also moved counter-clockwise and link members 16 are rotated to move the arms i3 of the intermediate member against the action of spring member 61. The toggle means including link members 1i is arranged so that as handle 14 is moved to on" position the center of pin 18 crosses the center line between the center of shaft 1I and pin 11 and then arm 1l abuts against the upper edges of arms B3 which may be provided with recesses 80 to permit such movement of said pin 18. Such toggle action maintains the intermediate member in a cocked position with the spring 61 acting to press arm 1l against the arms 63 or in the recess 80 therein. At the same time projection 19 is brought into the path of movement of switch arm Il and into position slightly above the normally closed switch arm Il and plate 65 is located so that the aperture 6i' therein permits switch arm Il to move to its normally closed position. Upon thermal operation of movement of the thermostatic switch arm 3| to open position, the projection ll is engaged by switch arm 3| and moved to return the center of pin 18 across the center line between shaft 1i and pin 11 whereupon the spring I1 acts to move said intermediate member to its upper extreme position and the manually operable mem- .ber to off position and the plate tl. as previously explained, engages projection l1 to hold switch arm 3| in open position. Oi course, the manually operable member or handle I4 may be manually moved in a clockwise direction to the on position for opening of the switch assembly at will.

In the switch assembly shown, the mechanical opening of the snap acting thermostatic switch arm 3| by the intermediate and manual operable members causes said switch arm li to assume a position likeI that caused by thermal opening thereof in that the curvature of said switch arm 8l is reversed as shown in Fig. 2. Mechanical opening of switch arm Il by ilexing it in the same or similar manner as by thermal operation 4 I Il isiiexedinthesamemannerasitisdesigned to be nexed thermally and the abrupt change in curvature ot the switch arm Ii also opens the contacts rapidly.

Since many variations ot the invention are possible, the present disclosure shall be construed in an illustrative sense and the scope of the invention is denned by the claims which follow.

Having now particularly described my invention what I desire to secure by Letters Patent o! the United States and what I claim is:

l. In a manually operable thermostatic switch assembly. the combination with a switch means including a bimetallic switch arm having a free end movable to opened and closed positions, an intermediate member pivotally mounted and carrying an extension provided with an aperture into which the free end of said switch arm extends and which aperture permits thermal operation of said bimetallic switch arm, resilient means normally urging said intermediate member to move the extension thereon so as to engage and open said switch arm, a link member pivotally connected at one end to said intermediate member, a manually operable member pivotally mounted and having an arm pivotally connected to the other end of said link member and movable to move said link and intermediate members against the action of said resilient means into an ineiective position and permit thermal operation of said blmetallic switch arm, the pivotal mounting oi said manually operable member and the pivotal connections between said link member and said arm and between said link member and said intermediate member being relatively located so as to form a toggle linkage holding said intermediate member in ineiiective position and so that said arm engages said intermediate member to limit the over-center movement of such toggle linkage, and a Projection on said link member in the path of movement of said switch arm during over-center positionof said toggle linkage and engaged and moved by said switch arm to release said toggle linkage and permit movement of said intermediate member by said resilient means to open said switch arm.

2. In a manually operable thermostatic switch assembly, the combination with a switch means including a bimetallic switch arm having a tree end movable to opened and closed positions, an intermediate member pivotally mounted, provided with a recess, and carrying an extension provided with an aperture into which the i'ree end of said switch arm extends and which aperture permits thermal operation of said bimetallic switch arm. resilient means normally biasing said intermediate member to move the extension thereon so as to engage and open said switch am a link member pivotally connected at one end to said intermediate member, a manually operable member pivotally mounted and having an arm pivotally connected to the other end of said link member and movable to move said link and intermediate members against the action of said resilient means into an ineective position-'and permit thermal operation of said bimetallic switch arm. the pivotal mounting of said manually operable member and the pivotal connections between said link member and said arm and between said link member and said intermediate member being relatively located so as to form a toggle linkage holding said intermediate member in ineii'ective position and so that said arm enters said recess and engages said intermediate memhas obvious advantages because the switch ann ber to limit the over-center movement ot such 5 toggle linkage. and a projection on said link member in the path of movement of said switch arm during over-center position of said toggle linkage and engaged and moved by said switch arm to release said toggle linkage and permit movement of said intermediate member by said resilient means to open said switch arm.

- FRANK ROBERT BEAN.

REFERENCES The following references are of record in the ille o! this patent:

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